1. Field of the Invention
The present invention relates to a robot cleaner, and particularly, to a robot cleaner capable of stably carrying out cleaning operation by sensing a depressed portion or a stepped portion such as a doorsill of a floor and thus by avoiding, passing, crossing over or going over such portions.
2. Description of the Background Art
A robot cleaner is a device that automatically moves in a cleaning area, carrying out cleaning operation, moves to a charging station when a charging voltage of a battery is decreased below a predetermined level, and returns to the cleaning area when the charging is completed to perform the cleaning operation.
The robot cleaner is provided with a suction unit for sucking foreign substances on a floor; a driving unit comprised of a driving motor and a driving wheel connected to the driving motor to move the robot cleaner; a navigation sensor for sensing a position and a cleaning area of the robot cleaner; and a control unit for automatically controlling the robot cleaner.
However, the conventional robot cleaner cannot continuously perform cleaning by falling to a depressed portion or being caught by a stepped portion such as a doorsill because it cannot sense the depressed portion making a relatively great height difference with a bottom of the robot cleaner or the stepped portion in the cleaning area.